diff --git a/ProjectDxLibEx.sln b/ProjectDxLibEx.sln
index 3ab83b7..b127a8b 100644
--- a/ProjectDxLibEx.sln
+++ b/ProjectDxLibEx.sln
@@ -19,6 +19,8 @@ Project("{8BC9CEB8-8B4A-11D0-8D11-00A0C91BC942}") = "UnitTest", "tests\UnitTest\
 EndProject
 Project("{8BC9CEB8-8B4A-11D0-8D11-00A0C91BC942}") = "WithDxLib", "tests\WithDxLib\WithDxLib.vcxproj", "{280349E1-6523-4483-97DB-2D16B0716396}"
 EndProject
+Project("{8BC9CEB8-8B4A-11D0-8D11-00A0C91BC942}") = "sound_play", "samples\sound_play\sound_play\sound_play.vcxproj", "{BF458CEF-25D4-4FA5-AFF9-BF4BA4C14AD4}"
+EndProject
 Global
 	GlobalSection(SolutionConfigurationPlatforms) = preSolution
 		clang_Debug|Win32 = clang_Debug|Win32
@@ -119,6 +121,22 @@ Global
 		{280349E1-6523-4483-97DB-2D16B0716396}.Release|Win32.ActiveCfg = Release|Win32
 		{280349E1-6523-4483-97DB-2D16B0716396}.Release|Win32.Build.0 = Release|Win32
 		{280349E1-6523-4483-97DB-2D16B0716396}.Release|x64.ActiveCfg = Release|Win32
+		{BF458CEF-25D4-4FA5-AFF9-BF4BA4C14AD4}.clang_Debug|Win32.ActiveCfg = clang_Debug|Win32
+		{BF458CEF-25D4-4FA5-AFF9-BF4BA4C14AD4}.clang_Debug|Win32.Build.0 = clang_Debug|Win32
+		{BF458CEF-25D4-4FA5-AFF9-BF4BA4C14AD4}.clang_Debug|x64.ActiveCfg = clang_Debug|x64
+		{BF458CEF-25D4-4FA5-AFF9-BF4BA4C14AD4}.clang_Debug|x64.Build.0 = clang_Debug|x64
+		{BF458CEF-25D4-4FA5-AFF9-BF4BA4C14AD4}.clang_Release|Win32.ActiveCfg = clang_Release|Win32
+		{BF458CEF-25D4-4FA5-AFF9-BF4BA4C14AD4}.clang_Release|Win32.Build.0 = clang_Release|Win32
+		{BF458CEF-25D4-4FA5-AFF9-BF4BA4C14AD4}.clang_Release|x64.ActiveCfg = clang_Release|x64
+		{BF458CEF-25D4-4FA5-AFF9-BF4BA4C14AD4}.clang_Release|x64.Build.0 = clang_Release|x64
+		{BF458CEF-25D4-4FA5-AFF9-BF4BA4C14AD4}.Debug|Win32.ActiveCfg = Debug|Win32
+		{BF458CEF-25D4-4FA5-AFF9-BF4BA4C14AD4}.Debug|Win32.Build.0 = Debug|Win32
+		{BF458CEF-25D4-4FA5-AFF9-BF4BA4C14AD4}.Debug|x64.ActiveCfg = Debug|x64
+		{BF458CEF-25D4-4FA5-AFF9-BF4BA4C14AD4}.Debug|x64.Build.0 = Debug|x64
+		{BF458CEF-25D4-4FA5-AFF9-BF4BA4C14AD4}.Release|Win32.ActiveCfg = Release|Win32
+		{BF458CEF-25D4-4FA5-AFF9-BF4BA4C14AD4}.Release|Win32.Build.0 = Release|Win32
+		{BF458CEF-25D4-4FA5-AFF9-BF4BA4C14AD4}.Release|x64.ActiveCfg = Release|x64
+		{BF458CEF-25D4-4FA5-AFF9-BF4BA4C14AD4}.Release|x64.Build.0 = Release|x64
 	EndGlobalSection
 	GlobalSection(SolutionProperties) = preSolution
 		HideSolutionNode = FALSE
@@ -129,5 +147,6 @@ Global
 		{D0B701B2-9FFB-45DC-A26E-4C9012E0D237} = {8301B3DC-D95E-4277-8614-FE1CF783AB18}
 		{44682BAF-4F62-42D9-90EB-D7F46CD21B95} = {373EF964-F08D-40C8-8543-221ADCE91DE5}
 		{280349E1-6523-4483-97DB-2D16B0716396} = {373EF964-F08D-40C8-8543-221ADCE91DE5}
+		{BF458CEF-25D4-4FA5-AFF9-BF4BA4C14AD4} = {8301B3DC-D95E-4277-8614-FE1CF783AB18}
 	EndGlobalSection
 EndGlobal
diff --git a/ProjectDxLibEx.vcxproj b/ProjectDxLibEx.vcxproj
index f1beb9f..329e3e0 100644
--- a/ProjectDxLibEx.vcxproj
+++ b/ProjectDxLibEx.vcxproj
@@ -18,6 +18,7 @@
     <ClInclude Include="dxlibex\algorithm\cast_if.hpp" />
     <ClInclude Include="dxlibex\algorithm\safe_dist.hpp" />
     <ClInclude Include="dxlibex\basic_types.hpp" />
+    <ClInclude Include="dxlibex\basic_types\bel.hpp" />
     <ClInclude Include="dxlibex\basic_types\use_big_type_when_one_byte_t.hpp" />
     <ClInclude Include="dxlibex\basic_types\coordinate_operator_bool_helper.hpp" />
     <ClInclude Include="dxlibex\basic_types\distance_result_type_t.hpp" />
@@ -61,6 +62,7 @@
     <ClInclude Include="dxlibex\type_traits\ignore.hpp" />
     <ClInclude Include="dxlibex\type_traits\is_castable.hpp" />
     <ClInclude Include="dxlibex\type_traits\is_nothrow.hpp" />
+    <ClInclude Include="dxlibex\type_traits\is_ratio.hpp" />
     <ClInclude Include="dxlibex\type_traits\is_representable.hpp" />
     <ClInclude Include="dxlibex\type_traits\is_well_format.hpp" />
   </ItemGroup>
diff --git a/ProjectDxLibEx.vcxproj.filters b/ProjectDxLibEx.vcxproj.filters
index e66d8e7..0a1a10d 100644
--- a/ProjectDxLibEx.vcxproj.filters
+++ b/ProjectDxLibEx.vcxproj.filters
@@ -182,5 +182,11 @@
     <ClInclude Include="dxlibex\Sound.h">
       <Filter>dxlibex</Filter>
     </ClInclude>
+    <ClInclude Include="dxlibex\basic_types\bel.hpp">
+      <Filter>dxlibex\basic_types</Filter>
+    </ClInclude>
+    <ClInclude Include="dxlibex\type_traits\is_ratio.hpp">
+      <Filter>dxlibex\type_traits</Filter>
+    </ClInclude>
   </ItemGroup>
 </Project>
\ No newline at end of file
diff --git a/dxlibex/basic_types/bel.hpp b/dxlibex/basic_types/bel.hpp
index b2a7b78..9c47be7 100644
--- a/dxlibex/basic_types/bel.hpp
+++ b/dxlibex/basic_types/bel.hpp
@@ -121,7 +121,8 @@ namespace dxle { namespace sound_units { namespace sound_units_literals {
 	inline DXLE_CONSTEXPR deci_bel operator "" _dB(unsigned long long myrioB) {
 		return deci_bel(static_cast<int>(myrioB));
 	}
-} } }
-using namespace dxle::sound_units::sound_units_literals;
+}
+using namespace sound_units_literals;
+}}
 #endif
 #endif //DXLE_INC_BASIC_TYPES_BEL_HPP_
diff --git a/samples/sound_play/sound_play/main.cpp b/samples/sound_play/sound_play/main.cpp
index 7b1d90b..0e46080 100644
--- a/samples/sound_play/sound_play/main.cpp
+++ b/samples/sound_play/sound_play/main.cpp
@@ -4,6 +4,7 @@
 int WINAPI WinMain(HINSTANCE /*hInstance*/, HINSTANCE /*hPrevInstance*/, LPSTR /*lpCmdLine*/, int /*nCmdShow*/) {
 	//SetCreateSoundPitchRate(100);
 #ifdef DXLE_SUPPORT_CXX11_USER_DEFINED_LITERALS
+	using namespace dxle::sound_units_literals;
 	constexpr auto rate = 300_dB;
 	constexpr auto rate2 = 4000_myrioB;
 	constexpr auto rate3 = dxle::bel_cast<dxle::bel>(rate);